Grinding attachment for lawn-mowers.



PATENTED JULY 14, 1908.

L. G. HAINES. GRINDING ATTACHMENT FOR LAWN MOWERS.

APPLICATION FILED 001?.2. 1907.

WW 9' amzowr A77'0RNEK LAWRENOE G. HAINES, OF GLAS SBORO, NEW JERSEY.

GRINDING ATTAGHIMENT FOR LAWN-MOWEBS..

v Specification of Letters Patent. 7

, Patented July 14, 1908.

Application filed October 2, 1907. Serial No. 895,651.

To all whom it may concern:

Be it known that I, LAWRENCE G. HAINES, a citizen of the United States, residing at Glassboro, in the county of Gloucester and of the'type in which a. rotary knife is used,

State of New Jerse have invented certain new and useful Improvements in Grinding Attachments for Lawn-Mowers, of which the following is a specification.

This invention relates to devices for sharpening lawn mowers and analogous machines and the rincipal object of the invention is to provide an im roved sharpening device for the rotary kn' e of such machines which may be readily applied to the frame of the machine and removed therefrom, and which is used to sharpen the blades of the rotary I knife only by reversing the movement of the rotary knife When the machine is not in actual use. i

A further object of the invention is to provide simple, inexpensive and eflicient means whereby the rotary knives of a mower mag be sharpened by a person unskilled in suc work.-

A still further ob'ect is to employ means which is ordinarily etached from'themower and is only a plied thereto when'it is'desired toshar en t erotary blades:

A sti further obje'ctis to rovide means whereby heel of the knives come in contact with the abrading surface of the device, thus producing an exceedingly keen edge. 1

Other objects will appear hereinafter. The invention consists of the improvements hereinafter described and eventually claimed.

The nature, characteristic features and sco e of the invention will be more fully un erstood from the following description taken in connection with the accompanying drawings forming part thereof, and in w ich Figure 1, is a view principally in sectionpf a lawn mower havin the attachment ofthe invention supplied t ereto and illustrating one mode of using a mower so as to reverse the usual motion of the cutting blades. Fig; 2, is a perspective view of the attachment embodying the invention. Fig. 3, is a fragmentary view of a portion-of the attachment.

attachment, and

V tached to and detached preferably by g g;

as the blades revolve ackward, the

'15 and 16. In

Fig. 4,.is a view pirincipally in section of the ig. 5, is a similar'view of a modified form of the invention.

Referring to the drawings, 1, represents a lawn mower having. driving Wheels 2, rotary lades 3, roller 4, and handle 5, all of which maybe of any preferred construction. Having adjustable relation with the frame 6, that supports the roller 4, are curved arms or brackets 7 slotted as at 8, and provided with openends 9. These arms after being erly adjusted may be secured to place and left upon the mower. Adapted to be atfrom these arms or brackets is a rectangular attachment 10, capable of adjustment with respect to the slotted arms or brackets in a manner to be hereinafter described. This rectangular attach ,mentIO, as shown,

I comprises a resilient metallic angular plate 11-11, preferably of tin, which may have a channeled edge 12. Applied to the part 11,01 this angular plate, is a sheet of emery cloth or other suitable abrading material 13. As shown in the drawings, this material 13, is secured at one end within the channel portion 12, anditsother end is secured by means of a plate 14, which extends along the part 11, of the angular plate-andwhich is secured thereto b means of screws 15 and nuts 16. aving s idable relation with the attachment and more to the plate 14, are slotted an ular brackets 17, which are secured to place y means of the aforesaid screws and nuts 15 and -16. .This adjustment is essential in order to accommodate the attachment to various sizes of mowers.

In order to provide stability to the attachend of the attachment one end of said springs being accommodated 'within the channel ortion 12 of the plate 11, the opposite en s of the springs being secured to the plate 11, as shown, by means of the screws and nuts practice the. brackets 7, as before described may be permanently attached to the mower and the brackets 17,

together .with the sharpening attachment and the butter-fly nuts 18, used for positioning the same, may be readily adjusted'with particularly with respect ment, leaf-springs 18, are provided at each respect to the slotted arms or brackets, access to the arms being had by virtue of the open ends 9.

The attachment is adjusted upon the mower when it is desired to sharpen the rotary blades 3, and is so arranged that as the blades revolve in a backward or reverse motion to that ordinarily used in cutting grass, the heel of the knives come in contact with the abrading surface 13, of the attachment 10, and thus produces a very keen cutting edge. By reason of the somewhat resilient character of the attachment 10, the blades contact with the same with a more or less slight pressure, and by reason thereof, .the blades are not unduly worn. In the modification shown in Fig. 5, the abrading surface 13*, is curved inwardly which permits of the blades 3, contacting through a greater are in their rotation which obviously provides a larger abrading surface, which is advantageous.

In practice it has been demonstrated that very good results have been obtained by sharpening the blades of a mower by revolving the blades backward. This method has been found necessary for the following reason: In rotating the blades in their ordinary direction, the cutting edge of the blades contact with the abrading surface and tends to round off, as it were, the cutting edge of the blade in contradistinction from producing the keen edge necessary to produce a clean out rather than a tearing out. By reversing the ordinary direction of rotation of the blades, the heel of the blades contact with the abrading surface first and as the blades further rotate, the bevel of the knives are drawn across the abrading surface and gradually effect a keen razor-like cutting edge. The mode of obtaining a reverse movement of the cutting blades depends entirely upon the make of lawn mower, and will be readily understood by those skilled in the art. However, the following explanation may tend toward a better understanding of the application of the attachment of the invention.

In some instances, the pawlin the small pinion that derives its motion from the main driving wheel and rotates the cutting blades of the machine may be reversed, the attachment put in place and the mower turned to the position s own in Fig. 1, and by pushing the same along the ground for-a short time will cause the blades to be sharpened where upon the attachment may be removed, the pawl returned to its original position and the mower used in the, ordinary manner. Some makes of mowers are rovided with an extension u on the blade s raft for the reception of a cran In this event, the mower may be lifted free of the ground, the attachment applied and the rotary blades revolved in a backward motion by means of said crank. It may be necessary in still other makes of mowers to resort to other means in order to obtain a reverse movement of the cutting blades, but this is not essential to this invention.

Having thus described the nature and objects of the invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination in a lawn mower of a sharpening device for the rotary knives thereof comprising a resilient plate having an abrading surface and laterally adjustable members, reinforcing members for said plate, adjustable brackets carried by the frame of the machine, means for adj ustably securing the aforesaid members with respect to said brackets, and means for causing the rotary blades of the mower to impinge against the abrading surface in a reverse or backward direction.

2. The combination in a lawn mower of a sharpening device for the rotary knives thereof comprising a resilient plate having an abrading surface and laterally adjustable angle brackets, reinforcing members for said plate arranged at each end thereof, adjustable arms carried by the frame of the mower, the aforesaid brackets being ad'ustably secured to said arms, and adapte for adjustable travel with respect thereto and means for causing the rotary blades to unhinge against said abrading surface in a reverse or backward rotation.

3. An attachment for lawn mowers comprising an angular member having a removable abrading surface, brackets adjustahly mounted in relation to said member, leaf springs at each end of the device for reinforcing the angular member and means for securing the springs to place.

4. An attachment for lawn mowers comprising an an ular member having a channeled edge and an inverted curved abrading surface, angular brackets adjustably mounted in relation to said member, and leaf springs at each end of the device, one end of said springs being secured to the angular member and the free ends of said springs being inserted within the channeled portions of the device.

5. A sharpening attachment for lawn mowers comprising a resilient plate having an inverted {LDC curved abrading surface and reinforcing members for the plate at each end thereof.

6. A sharpening attachment for lawn mowers comprising a resilient plate provided with a sheet of abrading material and having angle brackets laterally adjustable with respect to the, plate, means for reinforcing said resilient plate,sidearms carried'by the frame channeled edge and an angular extension and of the mower and adapted for concentric reinforcing members ateach end of the said adjustment with respect to the rotary blades plate, one of the ends of said reinforcing 5 o the mower and means for adjustablysemembers being'secured to the angular exten- 5 curing the'angle brackets to the side arms. sion and the free ends thereof being inserted- A' sharpening attachment for lawn within the channeled edge of .the plate. mowers comprising a comparatively thin an-v In-testimony whereof I have hereunto set gle plate provided with a removable Sheet of my hand. v abrading material and reinforcing members LAWRENCE G. HAINES. 10 for the said plate at each end thereof. Witnesses: I

8. A sharpening attachment for lawn WM. J. JACKSON, mowers comprising a resilient plate having a GRANT C. OSBORNE. 

